Flavor oils with reduced dimethyl sulfoxide content and use in oral compositions

ABSTRACT

The present invention relates to flavor oils including mint-, fruit- and spice-type flavors that are specially processed to substantially eliminate low-molecular weight sulfur compounds, in particular dimethyl sulfoxide (DMSO), which has been found to be the main precursor of malodorous species such as dimethyl sulfide and methyl mercaptan. These malodorous species are produced via oxidation-reduction reactions involving such sulfur-containing compounds present in flavor oils. A preferred processing method is an aqueous-washing process, which has advantages of being simple, inexpensive and easy to implement while importantly avoiding the problems of typical processes including non-selective removal of desirable components and subjecting the flavor oils to extreme conditions that may destroy other components and result in undesirable changes in flavor or odor character. Other processing methods to selectively remove non-desired components include (1) distillation to remove polar low boiling point components, (2) filtration through adsorbents selective for sulfur compounds, (3) countercurrent extraction and (4) column chromatography. The processing methods may optionally be followed by reengineering to add back desired components that may have been removed or altered during the processing. The specially processed flavor oils are particularly useful in oral care compositions comprising components with chemical reducing capability such as stannous ions, which react with the sulfur-containing compounds to produce malodorous products.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Nos.60/819,154 and 60/819,156, both filed Jul. 7, 2006.

TECHNICAL FIELD

The present invention relates to oral care compositions containing aflavor system comprising flavor oils that are stable against degradationand production of malodor and off-taste and mainly derived fromsulfur-containing species such as thiols or mercaptans. These malodorousspecies are produced via oxidation-reduction reactions involvingsulfur-containing compounds present in flavor oils and other componentsof the composition. The flavor oils are specially processed to reducethe content of low-molecular weight sulfur compounds, in particulardimethyl sulfoxide (DMSO), which has been found to be the main precursorof malodorous species such as dimethyl sulfide and methyl mercaptan. Thepresent invention thus provides methods to produce flavor oils,including mint-, fruit- and spice-type flavors that are substantiallyfree of DMSO and other sulfur-containing species and oral carecompositions incorporating such specially processed flavor oils forimproved stability in terms of taste and odor profile.

BACKGROUND OF THE INVENTION

Oral care products such as dentifrice and mouthrinse are routinely usedby consumers as part of their oral care hygiene regimens. It is wellknown that oral care products can provide both therapeutic and cosmetichygiene benefits to consumers. Therapeutic benefits include cariesprevention which is typically delivered through the use of variousfluoride salts; gingivitis prevention by the use of an antimicrobialagent such as triclosan, stannous fluoride, or essential oils; orhypersensitivity control through the use of ingredients such asstrontium chloride or potassium nitrate. Cosmetic benefits provided byoral care products include the control of plaque and calculus formation,removal and prevention of tooth stain, tooth whitening, breathfreshening, and overall improvements in mouth feel impression which canbe broadly characterized as mouth feel aesthetics. Calculus and plaquealong with behavioral and environmental factors lead to formation ofdental stains, significantly affecting the aesthetic appearance ofteeth. Behavioral and environmental factors that contribute to teethstaining propensity include regular use of coffee, tea, cola or tobaccoproducts, and also the use of certain oral products containingingredients that promote staining, such as cationic antimicrobials andmetal salts.

Thus daily oral care at home requires products with multiple ingredientsworking by different mechanisms to provide the complete range oftherapeutic and aesthetic benefits, including anticaries, antimicrobial,antigingivitis, antiplaque and anticalculus as well as antiodor, mouthrefreshment, stain removal, stain control and tooth whitening. In orderfor oral care products for daily use such as dentifrice and rinses toprovide complete oral care it is necessary to combine actives andadditives, many of which have the disadvantage of causing negativeaesthetics during use, in particular unpleasant taste and sensations andstain promotion. The unpleasant taste and mouth sensations have beendescribed as having one or more of bitter, metallic, astringent, salty,numbing, stinging, burning, prickling, and even irritating aspects.Typical ingredients for oral care use that are associated with theseaesthetic negatives include antimicrobial agents such as cetylpyridinium chloride, chlorhexidine, stannous, copper and zinc salts;tooth bleaching agents such as peroxides; antitartar agents such aspyrophosphate, tripolyphosphate and hexametaphosphate; and excipientssuch as baking soda and surfactants. To mitigate the aesthetic negativesfrom these ingredients, oral care products are typically formulated withflavoring agents and sweeteners to taste as good as possible and beconsumer acceptable.

Because of the many proven benefits to the oral cavity, stannous ionsare desired to be incorporated in oral care compositions. Stannous ions,typically supplied from stannous fluoride in oral care compositions areused to provide benefits including antimicrobial, anti-plaque,anti-gingivitis and anti-sensitivity and to prevent mouth malodor.However, formulating with stannous ions has proven to be challenging asformulations containing the stannous ions have been known to not beaesthetically pleasing. In addition, it has been found that certainflavoring oils, especially mint-type oils when used in combination withstannous ions can exhibit instability and malodor production.

Refining or further processing of natural flavor oils followingextraction from plants or plant materials, to improve quality andstability have been described in the art. Generally these processingmethods are aimed at removing or reducing the content in the oils ofcomponents believed to be responsible for instability or undesirabletaste or odor characteristics. For example, flavor oils have beentreated to remove or reduce the content of terpenes, menthofuran,pulegone and dimethyl sulfide. Such treatment processes are describedfor example in U.S. Pat. Nos. 3,867,262; 4,440,790; 4,613,513;4,708,880; 4,844,883; 4,816,616; 4,948,595; 5,116,625; 5,128,154;5,204,128; 5,298,238; 5,425,962; and 6,479,088, and includedistillation, nitrogen sparging, and chemical treatment to oxidize orinactivate such undesirable components.

Peppermint oils for example may be distilled to remove or reduce thelevel of dimethyl sulfide which is reported to provide an undesirablegreen weedy note. Steam or vacuum distillations have been performed torefine peppermint oil. However, such distillation processes are notentirely satisfactory. The typical steam distillation process inaddition to removing dimethyl sulfide also removes other low boilingpoint peppermint oil components. It is therefore necessary when refiningpeppermint oil to separate desirable low boiling components from thedistillate and add them back at least in part to the flavor. Thisincreases the cost and time of the distillation process. An additionalproblem with most currently used methods of refining peppermint oil isthat they may subject the peppermint oil to extreme conditions, such asexcessive heat. This can produce undesirable changes in the flavor.

There continues to be a need for improved processing of flavor oils toprovide optimum taste and odor characteristics and stability, inparticular to remove malodor-forming components specifically dimethylsulfoxide, which has now been found to be the major form ofmalodor-precursor sulfur species in flavor oils. The present inventionaccordingly involves the removal of such previously unrecognizedundesirable odor-forming components from starting flavor oil(s) withproduction of a stable flavor which is essentially free of undesirableamounts of such malodor-forming components and hence also free ofmalodor-forming or flavor contaminating tendencies due to reactions withreducing agents such as stannous in oral care compositions.

SUMMARY OF THE INVENTION

In one aspect the present invention is directed to further processing orrefining of flavor oils to reduce the content of sulfur-containingcompounds, such as dimethyl sulfoxide. A preferred processing method isan aqueous washing process, which has the advantages of being simple,inexpensive and easy to implement while importantly avoiding theproblems of typical processes including non-selective removal ofdesirable components and subjecting the flavor oils to extremeconditions that may destroy other components and result in undesirablechanges in flavor and odor character. Other processing methods toselectively remove non-desired components include (1) distillation toremove polar low boiling point components, (2) filtration throughadsorbents selective for sulfur compounds, (3) countercurrent extractionand (4) column chromatography. The processing methods may optionally befollowed by reengineering to add back desired components that may havebeen removed or altered during the processing.

In a further aspect, the invention provides oral care compositionscomprising

(a) an oral care agent having chemical reducing capability,

(b) a flavor system comprising flavor oil(s) or extract(s) essentiallyfree of sulfur-containing species including dimethyl sulfoxide, dimethylsulfide, dimethyl disulfide and dimethyl sulfone, responsible forgeneration of malodor and off-taste in said compositions, and

(c) an orally-acceptable carrier.

The oral care agent having chemical reducing capability is selected froma stannous ion source and phenolics from sources such as tea, cranberry,pomegranate and oak bark. The compositions have a stable, well-roundedflavor profile and are pleasant tasting and refreshing, therebyencouraging user compliance and frequent use.

These and other features, aspects, and advantages of the presentinvention will become evident to those skilled in the art from thedetailed description which follows.

DETAILED DESCRIPTION OF THE INVENTION

While the specification concludes with claims particularly pointing outand distinctly claiming the invention, it is believed that the presentinvention will be better understood from the following description.

All percentages and ratios used hereinafter are by weight of totalcomposition, unless otherwise indicated. All percentages, ratios, andlevels of ingredients referred to herein are based on the actual amountof the ingredient, and do not include solvents, fillers, or othermaterials with which the ingredient may be combined as a commerciallyavailable product, unless otherwise indicated.

All measurements referred to herein are made at 25° C. unless otherwisespecified.

Herein, “comprising” means that other steps and other components whichdo not affect the end result can be added. This term encompasses theterms “consisting of” and “consisting essentially of.”

As used herein, the word “include” and its variants, are intended to benon-limiting, such that recitation of items in a list is not to theexclusion of other like items that may also be useful in the materials,compositions, devices, and methods of this invention.

As used herein, the words “preferred”, “preferably” and variants referto embodiments of the invention that afford certain benefits, undercertain circumstances. However, other embodiments may also be preferred,under the same or other circumstances. Furthermore, the recitation ofone or more preferred embodiments does not imply that other embodimentsare not useful, and is not intended to exclude other embodiments fromthe scope of the invention.

By “oral care composition” is meant a product, which in the ordinarycourse of usage, is not intentionally swallowed for purposes of systemicadministration of particular therapeutic agents, but may be retained inthe oral cavity for a time sufficient to contact substantially all ofthe dental surfaces and/or oral tissues for purposes of oral activity.The oral care composition may be in various forms including toothpaste,dentifrice, tooth gel, subgingival gel, mouthrinse, mousse, foam,denture care product, mouthspray, lozenge, chewable tablet or chewinggum. The oral care composition may also be incorporated onto strips orfilms for direct application or attachment to oral surfaces.

The term “dentifrice”, as used herein, means paste, gel, or liquidformulations unless otherwise specified. The dentifrice composition maybe a single phase composition or may be a combination of two or moreseparate dentifrice compositions. The dentifrice composition may be inany desired form, such as deep striped, surface striped, multilayered,having the gel surrounding the paste, or any combination thereof. Eachdentifrice composition in a dentifrice comprising two or more separatedentifrice compositions may be contained in a physically separatedcompartment of a dispenser and dispensed side-by-side.

The term “dispenser”, as used herein, means any pump, tube, or containersuitable for dispensing compositions such as dentifrices.

The term “teeth”, as used herein, refers to natural teeth as well asartificial teeth or dental prosthesis.

The term “flavor oils” refers to essential oils used as flavoringagents, which are volatile oils distilled or expressed from plants andconstituents of these volatile oils. The term “flavor oils” as usedherein when referring to mint and mint-type oils includes various gradesof the oil typically referred to as prime natural or unfolded (freshlyextracted from plant source) and refined or rectified to standardize theoil and remove unwanted flavor/odor characters (e.g., by fractionaldistillation). The rectified grade is generally the commercial gradesupplied to end users for use as flavorings and perfumes. Typicalessential oils and their main constituents are those obtained forexample from thyme (thymol, carvacrol), oregano (carvacrol, terpenes),lemon (limonene, terpinene, phellandrene, pinene, citral), lemongrass(citral, methylheptenone, citronellal, geraniol), orange flower(linalool, β-pinene, limonene), orange (limonene, citral), anise(anethole, safrol), clove (eugenol, eugenyl acetate, caryophyllene),rose (geraniol, citronellol), rosemary (borneol, bornyl esters,camphor), geranium (geraniol, citronellol, linalool), lavender (linalylacetate, linalool), citronella (geraniol, citronellol, citronellal,camphene), eucalyptus (eucalyptol); peppermint (menthol, menthylesters), spearmint (carvone, limonene, pinene); wintergreen (methylsalicylate), camphor (safrole, acetaldehyde, camphor), bay (eugenol,myrcene, chavicol), cinnamon (cinnamaldehyde, cinnamyl acetate,eugenol), tea tree (terpinen-4-ol, cineole), and cedar leaf (α-thujone,β-thujone, fenchone). Essential oils, their composition and production,are described in detail in Kirk-Othmer Encyclopedia of ChemicalTechnology, 4^(th) Edition and in The Merck Index, 13^(th) Edition.

The term “orally acceptable carrier” includes safe and effectivematerials, excipients or additives used in oral care compositionsincluding but not limited to fluoride ion sources, anti-calculus oranti-tartar agents, buffers, abrasives such as silica, alkali metalbicarbonate salts, thickening materials, humectants, water, surfactants,titanium dioxide, flavoring agents, sweetening agents, xylitol, coloringagents, and mixtures thereof.

Active and other ingredients useful herein may be categorized ordescribed herein by their cosmetic and/or therapeutic benefit or theirpostulated mode of action or function. However, it is to be understoodthat the active and other ingredients useful herein can, in someinstances, provide more than one cosmetic and/or therapeutic benefit orfunction or operate via more than one mode of action. Therefore,classifications herein are made for the sake of convenience and are notintended to limit an ingredient to the particularly stated applicationor applications listed.

Herein, the terms “tartar” and “calculus” are used interchangeably andrefer to mineralized dental plaque biofilms.

The essential and optional components of the present compositions aredescribed in the following paragraphs.

Flavor System

The present compositions comprise a flavor system comprising flavor oilsthat are stable against degradation and production of off-notes andmalodor mainly derived from sulfur-containing species such as thiols ormercaptans. These malodorous species are produced viaoxidation-reduction reactions involving components of flavor oils andother components of the composition. More specifically, it has now beendiscovered that low-molecular weight sulfur compounds such as dimethylsulfoxide (DMSO) are present in certain natural flavor oils insufficient quantities to react with agents having fairly strong reducingcapability, i.e., can be easily oxidized, resulting in production ofmalodorous species including dimethyl sulfide and methyl mercaptan. Thepresent invention thus provides flavor oils, including mint-, fruit- andspice-type flavors that are specially processed to reduce the content ofDMSO and other sulfur-containing species and oral care compositionsincorporating such processed flavor oils for improved taste andstability. Preferably the processed flavor oils are essentially free ofsuch undesirable sulfur-containing species including dimethyl sulfoxide,dimethyl sulfide, dimethyl disulfide and dimethyl sulfone that can bereduced to malodorous species. Other sulfur-containing compounds maystill be present in the processed oil; however these do not appear to beproblematic in terms of malodor generation. By “essentially free” hereinis meant that the flavor oil comprises less than about 20 ppm ofsulfur-containing species that are malodor precursors. It has been foundthat formulating flavor oils containing greater than about 20 ppm ofsuch sulfur-containing species with agents such as stannous can resultin malodor production that has been described as “skunky”. Further, suchredox reactions leading to the malodor are disadvantageous in decreasingthe concentration of active stannous in the composition, thuspotentially decreasing efficacy. Preferably the level of malodorprecursor sulfur-containing species in the flavors oils after processingsuch as by water washing, is less than about 10 ppm, more preferablyless than about 1 ppm and even more preferred less than about 0.5 ppm ornone at all.

The present invention involves the discovery that the main malodorprecursor sulfur-containing species present in flavor oils is DMSO, withsamples having levels as high as 300 ppm or more. The following tableshows levels of DMSO and dimethyl sulfide (DMS) in spearmint andpeppermint samples. As shown below, the main species is DMSO;significantly lower amounts of DMS are found in the flavor oils.

TABLE 1 DMSO and DMS Levels in Feedstock Peppermint and Spearmint OilsSample DMSO (ppm, w/v) DMS (ppm, w/v) Peppermint Feedstock Sample 1 31810.3 Peppermint Feedstock Sample 2 312 22.1 Peppermint Feedstock Sample3 181 46.8 Spearmint (1% head cut) 235 <1 Peppermint oils supplied byI.P. Callison, Spearmint oil supplied by Labbeemint

The occurrence of DMSO in nature has been reported. For example,naturally occurring levels of DMSO in selected fruits, vegetables,grains and beverages are reported in J. Agric. Food Chem. 1981, 29, pp.1089-91. The highest level reported was in black tea beverage with 16ppm. In most samples, the level found was less than 1 ppm, with higherlevels found in concentrated or processed samples such as tomato paste.It was thought that the increase in DMSO levels may be due to oxidationof dimethyl sulfide (DMS) during commercial processing. DMS is foundextensively in nature and is responsible for the characteristic odor ofmany foods. DMSO was also reported to occur in spearmint oil [Anais deAcademia Brasileira de Ciencias, 1972, 44 (Suppl.), 273-7] and inpeppermint oil [Agric. Biol. Chem., 1980, 44(7), 1535-43]. There havebeen no reports of the levels discovered in the mint flavor oils herein.

Determination of the levels of dimethyl sulfoxide (DMSO) and dimethylsulfide (DMS) in mint oils was achieved via sample dilution followed byliquid injection into a GC-MS system. Briefly, calibration standardswere prepared by spiking known quantities of DMSO and DMS intopeppermint oil that was previously water washed to remove thesecomponents to below the lower limit of quantification. The water washingtechnique is in accordance with the present invention and described indetail below. Each standard and sample was prepared for analysis bydilution of a 200 μL aliquot with 800 μL of ethyl acetate containingstable-isotope labeled internal standards for DMSO (¹³C₂) and DMS (²H₆).Prepared standards and samples were analyzed by injecting a 1 μL aliquotinto a split/splitless inlet of an Agilent 6890 GC. The column effluentwas transferred to an Agilent 5973 single quadrupole mass spectrometer,which was operated in selected ion monitoring (SIM) mode. For eachanalyte, peak area ratios (analyte/internal standard) for thecalibration standards were plotted versus spiked analyte concentrations.Each unknown sample concentration was interpolated from thecorresponding calibration curve based on its measured analyte tointernal standard peak area ratio. Using these assay conditions, thenominal lower limit of quantification for both DMSO and DMS was 1 ppm(w/v) with upper limits for quantification of 500 and 100 ppm for DMSOand DMS, respectively.

The present flavor oils are generally used in oral care compositions atlevels of from about 0.001% to about 5%, by weight of the composition.Preferably, the flavor oil is present from about 0.01% to about 4%, morepreferably from about 0.05% to about 3%, and most preferably from about0.1% to about 2%. The flavor oil can be present as the entire flavorcomposition of an oral formulation or can be combined with otherselected flavor ingredients. Preferred flavor oils for use in oral carecompositions include those derived from Mentha species such as M.piperita (peppermint), M. arvensis (corn mint), M. spicata (U.S. nativespearmint), M. cardiaca (Scotch spearmint) and M. viridis Crispa(spearmint form China). It is desired that the oral care composition hasan overall minty taste in that mint is the most dominant flavor therein.

In addition to the select mint flavor oils above, the flavor system maycomprise additional flavor ingredients including but not limited to oilof wintergreen, clove bud oil, cassia, sage, parsley oil, marjoram,lemon, orange, cis-jasmone, 2,5-dimethyl-4-hydroxy-3(2H)-furanone,5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone, vanillin, ethyl vanillin,anisaldehyde, 3,4-methylenedioxybenzaldehyde, 3,4-dimethoxybenzaldehyde,4-hydroxybenzaldehyde, 2-methoxybenzaldehyde, benzaldehyde;cinnamaldehyde, hexyl cinnamaldehyde, alpha-methyl cinnamaldehyde,ortho-methoxy cinnamaldehyde, alpha-amyl cinnamaldehydepropenylguaethol, heliotropine, 4-cis-heptenal, diacetyl, methyl-ρ-tert-butylphenyl acetate, menthol, methyl salicylate, ethyl salicylate, 1-menthylacetate, oxanone, alpha-irisone, methyl cinnamate, ethyl cinnamate,butyl cinnamate, ethyl butyrate, ethyl acetate, methyl anthranilate,iso-amyl acetate, iso-amyl butyrate, allyl caproate, eugenol,eucalyptol, thymol, cinnamic alcohol, octanol, octanal, decanol,decanal, phenylethyl alcohol, benzyl alcohol, alpha-terpineol, linalool,limonene, citral, maltol, ethyl maltol, anethole, dihydroanethole,carvone, menthone, β-damascenone, ionone, gamma decalactone, gammanonalactone, and gamma undecalactone and mixtures thereof. Generallysuitable flavoring ingredients are those containing structural featuresand functional groups that are less prone to redox reactions. Theseinclude derivatives of flavor chemicals that are saturated or containstable aromatic rings or ester groups. Also suitable are flavorchemicals that may undergo some oxidation or degradation withoutresulting in a significant change in the flavor character or profile.The flavor ingredients may be provided as single or purified chemicalsor supplied in the composition by addition of natural oils or extractsthat have preferably undergone the present water-washing treatment orother refining to remove components that are relatively unstable and maydegrade and alter the desired flavor profile, resulting in a lessacceptable product from an organoleptic standpoint.

The flavor system may also include a protectant component that preventsgeneration of off odor and off taste in the composition such asdescribed in co-filed copending application entitled FLAVORS FOR ORALCOMPOSITIONS. Such protectants include carbonyl compounds such asascorbic acid; cis-jasmone; 2,5-dimethyl-4-hydroxy-3(2H)-furanone;5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone; vanillin; ethyl vanillin;anisaldehyde; 3,4-methylenedioxybenzaldehyde; 3,4-dimethoxybenzaldehyde;4-hydroxybenzaldehyde; 2-methyoxybenzaldehyde; 4-methoxybenzaldehyde;benzaldehyde; cinnamaldehyde; hexyl cinnamaldehyde; alpha-methylcinnamaldehyde; ortho-methoxy cinnamaldehyde; alpha-amyl cinnamaldehyde;and combinations thereof. Many of these protectants are flavoringredients.

The flavor system may further comprise cooling agents or coolants suchas menthol, menthyl esters, carboxamides, ketals, diols, and mixturesthereof. Examples of suitable coolants useful in the presentcompositions are the paramenthan carboxamide agents such asN-ethyl-p-menthan-3-carboxamide, known commercially as “WS-3”;N,2,3-trimethyl-2-isopropylbutanamide, known as “WS-23”;N-ρ-benzeneacetonitrile-menthanecarboxamide; and others in the seriessuch as WS-5, WS-11, WS-14 and WS-30. Additional suitable coolantsinclude 3-1-menthoxypropane-1,2-diol known as TK-10 manufactured byTakasago; menthone glycerol acetal (Frescolat® MGA); menthyl esters suchas menthyl acetate, menthyl acetoacetate, menthyl lactate (Frescolat® MLsupplied by Haarmann and Reimer), and monomenthyl succinate (under thetradename Physcool from V. Mane). The terms menthol and menthyl as usedherein include dextro- and levorotatory isomers of these compounds andracemic mixtures thereof. TK-10 is described in U.S. Pat. No. 4,459,425,Amano et al., issued Jul. 10, 1984. WS-3 and other agents are describedin U.S. Pat. No. 4,136,163, Watson, et al., issued Jan. 23, 1979.

The flavor system will typically include a sweetening agent. Suitablesweeteners include those well known in the art, including both naturaland artificial sweeteners. Some suitable water-soluble sweetenersinclude monosaccharides, disaccharides, polysaccharides and derivativessuch as xylose, ribose, glucose (dextrose), mannose, galactose, fructose(levulose), sucrose (sugar), maltose, invert sugar (a mixture offructose and glucose derived from sucrose), partially hydrolyzed starch,corn syrup solids, dihydrochalcones, monellin, steviosides,glycyrrhizin, xylitol and erythritol. Suitable water-soluble artificialsweeteners include soluble saccharin salts, i.e., sodium or calciumsaccharin salts, cyclamate salts, the sodium, ammonium or calcium saltof 3,4-dihydro-6-methyl-1,2,3-oxathiazine-4-one-2,2-dioxide, thepotassium salt of3,4-dihydro-6-methyl-1,2,3-oxathiazine-4-one-2,2-dioxide (acesulfame-K),the free acid form of saccharin, and the like. Other suitable sweetenersinclude dipeptide based sweeteners, such as L-aspartic acid derivedsweeteners, such as L-aspartyl-L-phenylalanine methyl ester (aspartame)and materials described in U.S. Pat. No. 3,492,131,L-alpha-aspartyl-N-(2,2,4,4-tetramethyl-3-thietanyl)-D-alaninamidehydrate, methyl esters of L-aspartyl-L-phenylglycerin andL-aspartyl-L-2,5,dihydrophenyl-glycine,L-aspartyl-2,5-dihydro-L-phenylalanine,L-aspartyl-L-(1-cyclohexyen)-alanine, and the like. Water-solublesweeteners derived from naturally occurring water-soluble sweeteners,such as a chlorinated derivative of ordinary sugar (sucrose), known, forexample, under the product description of sucralose as well as proteinbased sweeteners such as thaumatococus danielli (Thaumatin I and II) canbe used. The composition preferably contains from about 0.1% to about10% of sweetener, preferably from about 0.1% to about 1%, by weight.

In addition the flavor system may include salivating agents, warmingagents, and numbing agents. These agents are present in the compositionsat a level of from about 0.001% to about 10%, preferably from about 0.1%to about 1%, by weight of the composition. Suitable salivating agentsinclude Jambu® manufactured by Takasago. Examples of warming agents arecapsicum and nicotinate esters, such as benzyl nicotinate. Suitablenumbing agents include benzocaine, lidocaine, clove bud oil, andethanol.

Chemical Reducing Agents

The flavor system comprising the present specially processed flavor oilsand extracts are particularly useful in compositions comprising agentsthat have chemical reducing capability, in particular stannous ionswhich as described above is a preferred active in oral care compositionsbecause of its wide range of benefits and phenolics and derivativesderived from plant sources with useful antimicrobial, anti-inflammatoryand antioxidant activities. Many of these phenolics and derivatives arealso useful as flavoring agents.

Stannous ions have fairly strong reducing properties, being oxidized tostannic form when reacting with DMSO which in turn is reduced to themalodor species DMS and further to methyl mercaptan (CH₃SH). Thereaction of stannous with agents such as DMSO is undesirable not onlybecause of the production of malodorous species but also in decreasingthe level of stannous and thus the efficacy of the composition. Many ofthe phenolics used in oral care compositions as actives or flavor agentsare susceptible to oxidation, i.e., have reducing capability and canthus react with DMSO in the same manner as stannous.

The present compositions preferably include a stannous ion source,including stannous fluoride and/or other stannous salts. Stannousfluoride has been found to help in the reduction of caries, gingivitis,plaque and sensitivity, and in improved breath benefits. Other stannoussalts include stannous chloride dihydrate, stannous acetate, stannousgluconate, stannous oxalate, stannous sulfate, stannous lactate, andstannous tartrate. The preferred stannous ion sources are stannousfluoride and stannous chloride dihydrate. The stannous salt(s) will bepresent in an amount of from about 0.1% to about 11%, by weight of thetotal composition. Preferably, the stannous salts are present in anamount of from about 0.4% to about 7%, more preferably from about 0.45%to about 5%, and most preferably from about 0.45% to about 3% by weightof the total composition. Formulations providing efficacy typicallyinclude stannous levels, provided by stannous fluoride and otherstannous salts, ranging from about 3,000 ppm to about 15,000 ppmstannous ions in the total composition.

Dentifrices containing stannous salts, particularly stannous fluorideand stannous chloride, are described in U.S. Pat. No. 5,004,597 toMajeti et al. Other descriptions of stannous salts are found in U.S.Pat. No. 5,578,293 issued to Prencipe et al. and in U.S. Pat. No.5,281,410 issued to Lukacovic et al. In addition to the stannous ionsource, other ingredients needed to stabilize the stannous may beincluded, such as the ingredients described in Majeti et al. andPrencipe et al.

Phenolics from plant sources such as tea, cranberry, pomegranate and oakbark may also be incorporated in the present compositions. Suchphenolics include catechin, gallocatechin gallate, epicatechin (EC),epigallocatechin (EGC), epigallocatechin gallate (EGCG), epicatechingallate (ECG), theaflavine, thearubigins,anthocyanidins/proanthocyanidins and anthocyanins (e.g., cyanidin,delphinidin, pelargonidin, peonidin, malvidin and petunidin); tannicacid; gallic acid; ellagic acid; ellagitannins; curcumin. The phenolicsmay be supplied as purified compounds or as plant extracts. Phenolicsuseful as oral care actives are disclosed in commonly assigned U.S.patent application Ser. No. 11/595,530, published as US 2007/0053849A1.

In addition to the components described above, the present compositionsmay comprise additional optional components collectively referred to asorally acceptable carrier materials, which are described in thefollowing paragraphs.

Orally Acceptable Carrier Materials

The orally acceptable carrier comprises one or more compatible solid orliquid excipients or diluents which are suitable for topical oraladministration. By “compatible,” as used herein, is meant that thecomponents of the composition are capable of being comingled withoutinteraction in a manner which would substantially reduce thecomposition's stability and/or efficacy.

The carriers or excipients of the present invention can include theusual and conventional components of dentifrices, non-abrasive gels,subgingival gels, mouthwashes or rinses, mouth sprays, chewing gums,lozenges and breath mints as more fully described hereinafter.

The choice of a carrier to be used is basically determined by the waythe composition is to be introduced into the oral cavity. Carriermaterials for toothpaste, tooth gel or the like include abrasivematerials, sudsing agents, binders, humectants, flavoring and sweeteningagents, etc. as disclosed in e.g., U.S. Pat. No. 3,988,433 to Benedict.Carrier materials for biphasic dentifrice formulations are disclosed inU.S. Pat. No. 5,213,790, issued May 23, 1993; 5,145,666, issued Sep. 8,1992; and U.S. Pat. No. 5,281,410 issued Jan. 25, 1994 all to Lukacovicet al. and in U.S. Pat. Nos. 4,849,213 and 4,528,180 to Schaeffer.Mouthwash, rinse or mouth spray carrier materials typically includewater, flavoring and sweetening agents, etc., as disclosed in, e.g.,U.S. Pat. No. 3,988,433 to Benedict. Lozenge carrier materials typicallyinclude a candy base; chewing gum carrier materials include a gum base,flavoring and sweetening agents, as in, e.g., U.S. Pat. No. 4,083,955 toGrabenstetter et al. Sachet carrier materials typically include a sachetbag, flavoring and sweetening agents. For subgingival gels used fordelivery of actives into the periodontal pockets or around theperiodontal pockets, a “subgingival gel carrier” is chosen as disclosedin, e.g. U.S. Pat. Nos. 5,198,220 and 5,242,910, issued Mar. 30, 1993and Sep. 7, 1993, respectively both to Damani. Carriers suitable for thepreparation of compositions of the present invention are well known inthe art. Their selection will depend on secondary considerations liketaste, cost, and shelf stability, etc.

The compositions of the present invention may also be in the form ofnon-abrasive gels and subgingival gels, which may be aqueous ornon-aqueous. In still another aspect, the invention provides a dentalimplement impregnated with the present composition. The dental implementcomprises an implement for contact with teeth and other tissues in theoral cavity, said implement being impregnated with the presentcomposition. The dental implement can be impregnated fibers includingdental floss or tape, chips, strips, films and polymer fibers.

In one embodiment, the compositions of the subject invention are in theform of dentifrices, such as toothpastes, tooth gels and tooth powders.Components of such toothpaste and tooth gels generally include one ormore of a dental abrasive (from about 6% to about 50%), a surfactant(from about 0.5% to about 10%), a thickening agent (from about 0.1% toabout 5%), a humectant (from about 10% to about 55%), a flavoring agent(from about 0.04% to about 2%), a sweetening agent (from about 0.1% toabout 3%), a coloring agent (from about 0.01% to about 0.5%) and water(from about 2% to about 45%). Such toothpaste or tooth gel may alsoinclude one or more of an anticaries agent (from about 0.05% to about0.3% as fluoride ion) and an anticalculus agent (from about 0.1% toabout 13%). Tooth powders, of course, contain substantially allnon-liquid components.

Other embodiments of the subject invention are liquid products,including mouthwashes or rinses, mouth sprays, dental solutions andirrigation fluids. Components of such mouthwashes and mouth spraystypically include one or more of water (from about 45% to about 95%),ethanol (from about 0% to about 25%), a humectant (from about 0% toabout 50%), a surfactant (from about 0.01% to about 7%), a flavoringagent (from about 0.04% to about 2%), a sweetening agent (from about0.1% to about 3%), and a coloring agent (from about 0.001% to about0.5%). Such mouthwashes and mouth sprays may also include one or more ofan anticaries agent (from about 0.05% to about 0.3% as fluoride ion) andan anticalculus agent (from about 0.1% to about 3%). Components ofdental solutions generally include one or more of water (from about 90%to about 99%), preservative (from about 0.01% to about 0.5%), thickeningagent (from 0% to about 5%), flavoring agent (from about 0.04% to about2%), sweetening agent (from about 0.1% to about 3%), and surfactant(from 0% to about 5%).

Types of orally acceptable carriers or excipients which may be includedin compositions of the present invention, along with specificnon-limiting examples, are discussed in the following paragraphs.

Tooth Substantive Agent

The present invention may include a tooth substantive agent such aspolymeric surface active agents (PMSA's), which are polyelectrolytes,more specifically anionic polymers. The PMSA's contain anionic groups,e.g., phosphate, phosphonate, carboxy, or mixtures thereof, and thus,have the capability to interact with cationic or positively chargedentities. The “mineral” descriptor is intended to convey that thesurface activity or substantivity of the polymer is toward mineralsurfaces such as calcium phosphate minerals or teeth.

PMSA's are useful in the present compositions because of their stainprevention benefit. It is believed the PMSA's provide a stain preventionbenefit because of their reactivity or substantivity to mineralsurfaces, resulting in desorption of portions of undesirable adsorbedpellicle proteins, in particular those associated with binding colorbodies that stain teeth, calculus development and attraction ofundesirable microbial species. The retention of these PMSA's on teethcan also prevent stains from accruing due to disruption of binding sitesof color bodies on tooth surfaces.

The ability of PMSA's to bind stain promoting ingredients of oral careproducts such as stannous ions and cationic antimicrobials is alsobelieved to be helpful. The PMSA will also provide tooth surfaceconditioning effects which produce desirable effects on surfacethermodynamic properties and surface film properties, which impartimproved clean feel aesthetics both during and most importantly,following rinsing or brushing. Many of these polymeric agents are alsoknown or expected to provide tartar control benefits when applied inoral compositions, hence providing improvement in both the appearance ofteeth and their tactile impression to consumers.

The desired surface effects include: 1) creating a hydrophilic toothsurface immediately after treatment; and 2) maintaining surfaceconditioning effects and control of pellicle film for extended periodsfollowing product use, including post brushing or rinsing and throughoutmore extended periods. The effect of creating an increased hydrophilicsurface can be measured in terms of a relative decrease in water contactangles. The hydrophilic surface, importantly, is maintained on the toothsurface for an extended period after using the product.

The polymeric mineral surface active agents include any agent which willhave a strong affinity for the tooth surface, deposit a polymer layer orcoating on the tooth surface and produce the desired surfacemodification effects. Suitable examples of such polymers arepolyelectrolytes such as condensed phosphorylated polymers;polyphosphonates; copolymers of phosphate- or phosphonate-containingmonomers or polymers with other monomers such as ethylenicallyunsaturated monomers and amino acids or with other polymers such asproteins, polypeptides, polysaccharides, poly(acrylate),poly(acrylamide), poly(methacrylate), poly(ethacrylate),poly(hydroxyalkylmethacrylate), poly(vinyl alcohol), poly(maleicanhydride), poly(maleate) poly(amide), poly(ethylene amine),poly(ethylene glycol), poly(propylene glycol), poly(vinyl acetate) andpoly(vinyl benzyl chloride); polycarboxylates and carboxy-substitutedpolymers; and mixtures thereof. Suitable polymeric mineral surfaceactive agents include the carboxy-substituted alcohol polymers describedin U.S. Pat. Nos. 5,292,501; 5,213,789, 5,093,170; 5,009,882; and4,939,284; all to Degenhardt et al. and the diphosphonate-derivatizedpolymers in U.S. Pat. No. 5,011,913 to Benedict et al; the syntheticanionic polymers including polyacrylates and copolymers of maleicanhydride or acid and methyl vinyl ether (e.g., Gantrez), as described,for example, in U.S. Pat. No. 4,627,977, to Gaffar et al. A preferredpolymer is diphosphonate modified polyacrylic acid. Polymers withactivity must have sufficient surface binding propensity to desorbpellicle proteins and remain affixed to enamel surfaces. For toothsurfaces, polymers with end or side chain phosphate or phosphonatefunctions are preferred although other polymers with mineral bindingactivity may prove effective depending upon adsorption affinity.

Additional examples of suitable phosphonate containing polymeric mineralsurface active agents include the geminal diphosphonate polymersdisclosed as anticalculus agents in U.S. Pat. No. 4,877,603 toDegenhardt et al; phosphonate group containing copolymers disclosed inU.S. Pat. No. 4,749,758 to Dursch et al. and in GB 1,290,724 (bothassigned to Hoechst) suitable for use in detergent and cleaningcompositions; and the copolymers and cotelomers disclosed as useful forapplications including scale and corrosion inhibition, coatings, cementsand ion-exchange resins in U.S. Pat. No. 5,980,776 to Zakikhani et al.and U.S. Pat. No. 6,071,434 to Davis et al. Additional polymers includethe water-soluble copolymers of vinylphosphonic acid and acrylic acidand salts thereof disclosed in GB 1,290,724 wherein the copolymerscontain from about 10% to about 90% by weight vinylphosphonic acid andfrom about 90% to about 10% by weight acrylic acid, more particularlywherein the copolymers have a weight ratio of vinylphosphonic acid toacrylic acid of 70% vinylphosphonic acid to 30% acrylic acid; 50%vinylphosphonic acid to 50% acrylic acid; or 30% vinylphosphonic acid to70% acrylic acid. Other suitable polymers include the water solublepolymers disclosed by Zakikhani and Davis prepared by copolymerizingdiphosphonate or polyphosphonate monomers having one or more unsaturatedC═C bonds (e.g., vinylidene-1,1-diphosphonic acid and2-(hydroxyphosphinyl)ethylidene-1,1-diphosphonic acid), with at leastone further compound having unsaturated C═C bonds (e.g., acrylate andmethacrylate monomers), such as those having the following structure:

1. Co-telomer of acrylic acid and2-(hydroxyphosphinyl)ethylidene-1,1-diphosphonic acid with structure:

2. Co-polymer of acrylic acid and vinyldiphosphonic acid with structure:

Suitable polymers include the diphosphonate/acrylate polymers suppliedby Rhodia under the designation ITC 1087 (Average MW 3000-60,000) andPolymer 1154 (Average MW 6000-55,000).

A preferred PMSA will be stable with other components of the oral carecomposition such as ionic fluoride and metal ions. Also preferred arepolymers that have limited hydrolysis in high water contentformulations, thus permitting a simple single phase dentifrice ormouthrinse formulation. If the PMSA does not have these stabilityproperties, one option is a dual phase formulation with the polymericmineral surface active agent separated from the fluoride or otherincompatible component. Another option is to formulate non-aqueous,essentially non-aqueous or limited water compositions to minimizereaction between the PMSA and other components.

A preferred PMSA is a polyphosphate. A polyphosphate is generallyunderstood to consist of two or more phosphate molecules arrangedprimarily in a linear configuration, although some cyclic derivativesmay be present. Although pyrophosphates (n=2) are technicallypolyphosphates, the polyphosphates desired are those having around threeor more phosphate groups so that surface adsorption at effectiveconcentrations produces sufficient non-bound phosphate functions, whichenhance the anionic surface charge as well as hydrophilic character ofthe surfaces. The inorganic polyphosphate salts desired includetripolyphosphate, tetrapolyphosphate and hexametaphosphate, amongothers. Polyphosphates larger than tetrapolyphosphate usually occur asamorphous glassy materials. Preferred in this invention are the linearpolyphosphates having the formula:XO(XPO₃)_(n)Xwherein X is sodium, potassium or ammonium and n averages from about 3to about 125. Preferred polyphosphates are those having n averaging fromabout 6 to about 21, such as those commercially known as Sodaphos (n≈6),Hexaphos (n≈13), and Glass H (n≈21) and manufactured by FMC Corporationand Astaris. These polyphosphates may be used alone or in combination.Polyphosphates are susceptible to hydrolysis in high water formulationsat acid pH, particularly below pH 5. Thus it is preferred to uselonger-chain polyphosphates, in particular Glass H with an average chainlength of about 21. It is believed such longer-chain polyphosphates whenundergoing hydrolysis produce shorter-chain polyphosphates which arestill effective to deposit onto teeth and provide a stain preventivebenefit.

Other polyphosphorylated compounds may be used in addition to or insteadof the polyphosphate, in particular polyphosphorylated inositolcompounds such as phytic acid, myo-inositol pentakis(dihydrogenphosphate); myo-inositol tetrakis(dihydrogen phosphate), myo-inositoltrikis(dihydrogen phosphate), and an alkali metal, alkaline earth metalor ammonium salt thereof. Preferred herein is phytic acid, also known asmyo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) or inositolhexaphosphoric acid, and its alkali metal, alkaline earth metal orammonium salts. Herein, the term “phytate” includes phytic acid and itssalts as well as the other polyphosphorylated inositol compounds.

The amount of tooth substantive agent will typically be from about 0.1%to about 35% by weight of the total oral composition. In dentifriceformulations, the amount is preferably from about 2% to about 30%, morepreferably from about 5% to about 25%, and most preferably from about 6%to about 20%. In mouthrinse compositions, the amount of toothsubstantive agent is preferably from about 0.1% to 5% and morepreferably from about 0.5% to about 3%.

In addition to creating the surface modifying effects, the toothsubstantive agent may also function to solubilize insoluble salts. Forexample, Glass H polyphosphate has been found to solubilize insolublestannous salts. Thus, in compositions containing stannous salts forexample, Glass H contributes to decreasing the stain promoting effect ofstannous.

Fluoride Source

It is common to have a water-soluble fluoride compound present indentifrices and other oral compositions in an amount sufficient to givea fluoride ion concentration in the composition, and/or when it is usedof from about 0.0025% to about 5.0% by weight, preferably from about0.005% to about 2.0% by weight, to provide anticaries effectiveness. Awide variety of fluoride ion-yielding materials can be employed assources of soluble fluoride in the present compositions. Examples ofsuitable fluoride ion-yielding materials are found in U.S. Pat. No.3,535,421, Oct. 20, 1970 to Briner et al. and U.S. Pat. No. 3,678,154,Jul. 18, 1972 to Widder et al. Representative fluoride ion sourcesinclude: stannous fluoride, sodium fluoride, potassium fluoride, sodiummonofluorophosphate, indium fluoride and many others. Stannous fluorideand sodium fluoride are preferred, as well as mixtures thereof.

Abrasives

Dental abrasives useful in the compositions of the subject inventioninclude many different materials. The material selected must be onewhich is compatible within the composition of interest and does notexcessively abrade dentin. Suitable abrasives include, for example,silicas including gels and precipitates, insoluble sodiumpolymetaphosphate, hydrated alumina, calcium carbonate, dicalciumorthophosphate dihydrate, calcium pyrophosphate, tricalcium phosphate,calcium polymetaphosphate, and resinous abrasive materials such asparticulate condensation products of urea and formaldehyde.

Another class of abrasives for use in the present compositions is theparticulate thermo-setting polymerized resins as described in U.S. Pat.No. 3,070,510 issued to Cooley & Grabenstetter on Dec. 25, 1962.Suitable resins include, for example, melamines, phenolics, ureas,melamine-ureas, melamine-formaldehydes, urea-formaldehyde,melamine-urea-formaldehydes, cross-linked epoxides, and cross-linkedpolyesters.

Silica dental abrasives of various types are preferred because of theirunique benefits of exceptional dental cleaning and polishing performancewithout unduly abrading tooth enamel or dentine. The silica abrasivepolishing materials herein, as well as other abrasives, generally havean average particle size ranging between about 0.1 to about 30 microns,and preferably from about 5 to about 15 microns. The abrasive can beprecipitated silica or silica gels such as the silica xerogels describedin Pader et al., U.S. Pat. No. 3,538,230, issued Mar. 2, 1970, andDiGiulio, U.S. Pat. No. 3,862,307, issued Jan. 21, 1975. Examplesinclude the silica xerogels marketed under the trade name “Syloid” bythe W.R. Grace & Company, Davison Chemical Division and precipitatedsilica materials such as those marketed by the J. M. Huber Corporationunder the trade name, Zeodent®, particularly the silicas carrying thedesignation Zeodent® 119, Zeodent® 118, Zeodent® 109 and Zeodent® 129.The types of silica dental abrasives useful in the toothpastes of thepresent invention are described in more detail in Wason, U.S. Pat. No.4,340,583, issued Jul. 29, 1982; and in commonly-assigned U.S. Pat. No.5,603,920, issued on Feb. 18, 1997; U.S. Pat. No. 5,589,160, issued Dec.31, 1996; U.S. Pat. No. 5,658,553, issued Aug. 19, 1997; U.S. Pat. No.5,651,958, issued Jul. 29, 1997, and U.S. Pat. No. 6,740,311, issued May25, 2004.

Mixtures of abrasives can be used such as mixtures of the various gradesof Zeodent® silica abrasives listed above. The total amount of abrasivein dentifrice compositions of the subject invention typically range fromabout 6% to about 70% by weight; toothpastes preferably contain fromabout 10% to about 50% of abrasives, by weight of the composition.Dental solution, mouth spray, mouthwash and non-abrasive gelcompositions of the subject invention typically contain little or noabrasive.

Anticalculus Agent

The present compositions may optionally include an additionalanticalculus agent, such as a pyrophosphate salt as a source ofpyrophosphate ion. The pyrophosphate salts useful in the presentcompositions include the dialkali metal pyrophosphate salts, tetraalkalimetal pyrophosphate salts, and mixtures thereof. Disodium dihydrogenpyrophosphate (Na₂H₂P₂O₇), tetrasodium pyrophosphate (Na₄P₂O₇), andtetrapotassium pyrophosphate (K₄P₂O₇) in their unhydrated as well ashydrated forms are the preferred species. In compositions of the presentinvention, the pyrophosphate salt may be present in one of three ways:predominately dissolved, predominately undissolved, or a mixture ofdissolved and undissolved pyrophosphate.

Compositions comprising predominately dissolved pyrophosphate refer tocompositions where at least one pyrophosphate ion source is in an amountsufficient to provide at least about 1.0% free pyrophosphate ions. Theamount of free pyrophosphate ions may be from about 1% to about 15%,from about 1.5% to about 10% in one embodiment, and from about 2% toabout 6% in another embodiment. Free pyrophosphate ions may be presentin a variety of protonated states depending on the pH of thecomposition.

Compositions comprising predominately undissolved pyrophosphate refer tocompositions containing no more than about 20% of the totalpyrophosphate salt dissolved in the composition, preferably less thanabout 10% of the total pyrophosphate dissolved in the composition.Tetrasodium pyrophosphate salt is a preferred pyrophosphate salt inthese compositions. Tetrasodium pyrophosphate may be the anhydrous saltform or the decahydrate form, or any other species stable in solid formin the dentifrice compositions. The salt is in its solid particle form,which may be its crystalline and/or amorphous state, with the particlesize of the salt preferably being small enough to be aestheticallyacceptable and readily soluble during use. The amount of pyrophosphatesalt useful in making these compositions is any tartar control effectiveamount, generally from about 1.5% to about 15%, preferably from about 2%to about 10%, and most preferably from about 3% to about 8%, by weightof the dentifrice composition.

Compositions may also comprise a mixture of dissolved and undissolvedpyrophosphate salts. Any of the above mentioned pyrophosphate salts maybe used.

The pyrophosphate salts are described in more detail in Kirk-OthmerEncyclopedia of Chemical Technology, 3rd Edition, Volume 17,Wiley-Interscience Publishers (1982).

Optional agents to be used in place of or in combination with thepyrophosphate salt include such known materials as synthetic anionicpolymers, including polyacrylates and copolymers of maleic anhydride oracid and methyl vinyl ether (e.g., Gantrez), as described, for example,in U.S. Pat. No. 4,627,977, to Gaffar et al., as well as, e.g.,polyamino propane sulfonic acid (AMPS), diphosphonates (e.g., EHDP;AHP), polypeptides (such as polyaspartic and polyglutamic acids), andmixtures thereof.

Chelating Agents

Another optional agent is a chelating agent, also called sequestrants,such as gluconic acid, tartaric acid, citric acid andpharmaceutically-acceptable salts thereof. Chelating agents are able tocomplex calcium found in the cell walls of the bacteria. Chelatingagents can also disrupt plaque by removing calcium from the calciumbridges which help hold this biomass intact. However, it is not desiredto use a chelating agent which has an affinity for calcium that is toohigh, as this may result in tooth demineralization, which is contrary tothe objects and intentions of the present invention. Suitable chelatingagents will generally have a calcium binding constant of about 10¹ to10⁵ to provide improved cleaning with reduced plaque and calculusformation. Chelating agents also have the ability to complex withmetallic ions and thus aid in preventing their adverse effects on thestability or appearance of products. Chelation of ions, such as iron orcopper, helps retard oxidative deterioration of finished products.

Examples of suitable chelating agents are sodium or potassium gluconateand citrate; citric acid/alkali metal citrate combination; disodiumtartrate; dipotassium tartrate; sodium potassium tartrate; sodiumhydrogen tartrate; potassium hydrogen tartrate; sodium, potassium orammonium polyphosphates and mixtures thereof. The amounts of chelatingagent suitable for use in the present invention are about 0.1% to about2.5%, preferably from about 0.5% to about 2.5% and more preferably fromabout 1.0% to about 2.5%.

Still other chelating agents suitable for use in the present inventionare the anionic polymeric polycarboxylates. Such materials are wellknown in the art, being employed in the form of their free acids orpartially or preferably fully neutralized water soluble alkali metal(e.g. potassium and preferably sodium) or ammonium salts. Examples are1:4 to 4:1 copolymers of maleic anhydride or acid with anotherpolymerizable ethylenically unsaturated monomer, preferably methyl vinylether (methoxyethylene) having a molecular weight (M.W.) of about 30,000to about 1,000,000. These copolymers are available for example asGantrez AN 139 (M.W. 500,000), AN 119 (M.W. 250,000) and S-97Pharmaceutical Grade (M.W. 70,000), of GAF Chemicals Corporation.

Other operative polymeric polycarboxylates include the 1:1 copolymers ofmaleic anhydride with ethyl acrylate, hydroxyethyl methacrylate,N-vinyl-2-pyrrolidone, or ethylene, the latter being available forexample as Monsanto EMA No. 1103, M.W. 10,000 and EMA Grade 61, and 1:1copolymers of acrylic acid with methyl or hydroxyethyl methacrylate,methyl or ethyl acrylate, isobutyl vinyl ether or N-vinyl-2-pyrrolidone.

Additional operative polymeric polycarboxylates are disclosed in U.S.Pat. No. 4,138,477, Feb. 6, 1979 to Gaffar and U.S. Pat. No. 4,183,914,Jan. 15, 1980 to Gaffar et al. and include copolymers of maleicanhydride with styrene, isobutylene or ethyl vinyl ether; polyacrylic,polyitaconic and polymaleic acids; and sulfoacrylic oligomers of M.W. aslow as 1,000 available as Uniroyal ND-2.

Other Active Agents

The present invention may optionally include other agents, such asantimicrobial agents. Included among such agents are water insolublenon-cationic antimicrobial agents such as halogenated diphenyl ethers,phenolic compounds including phenol and its homologs, mono andpoly-alkyl and aromatic halophenols, resorcinol and its derivatives,bisphenolic compounds and halogenated salicylanilides, benzoic esters,and halogenated carbanilides. The water soluble antimicrobials includequaternary ammonium salts and bis-biquanide salts, and triclosanmonophosphate. The quaternary ammonium agents include those in which oneor two of the substitutes on the quaternary nitrogen has a carbon chainlength (typically alkyl group) from about 8 to about 20, typically fromabout 10 to about 18 carbon atoms while the remaining substitutes(typically alkyl or benzyl group) have a lower number of carbon atoms,such as from about 1 to about 7 carbon atoms, typically methyl or ethylgroups. Dodecyl trimethyl ammonium bromide, tetradecylpyridiniumchloride, domiphen bromide, N-tetradecyl-4-ethyl pyridinium chloride,dodecyl dimethyl (2-phenoxyethyl) ammonium bromide, benzyldimethylstearyl ammonium chloride, cetyl pyridinium chloride,quaternized 5-amino-1,3-bis(2-ethyl-hexyl)-5-methyl hexahydropyrimidine, benzalkonium chloride, benzethonium chloride and methylbenzethonium chloride are exemplary of typical quaternary ammoniumantibacterial agents. Other compounds arebis[4-(R-amino)-1-pyridinium]alkanes as disclosed in U.S. Pat. No.4,206,215, issued Jun. 3, 1980, to Bailey. Other antimicrobials such ascopper salts, zinc salts and stannous salts may also be included. Alsouseful are enzymes, including endoglycosidase, papain, dextranase,mutanase, and mixtures thereof. Such agents are disclosed in U.S. Pat.No. 2,946,725, Jul. 26, 1960, to Norris et al. and in U.S. Pat. No.4,051,234, Sep. 27, 1977 to Gieske et al. Preferred antimicrobial agentsinclude zinc salts, stannous salts, cetyl pyridinium chloride,chlorhexidine, triclosan, triclosan monophosphate, and flavor oils suchas thymol. Triclosan and other agents of this type are disclosed inParran, Jr. et al., U.S. Pat. No. 5,015,466, issued May 14, 1991, andU.S. Pat. No. 4,894,220, Jan. 16, 1990 to Nabi et al. These agentsprovide anti-plaque benefits and are typically present at levels of fromabout 0.01% to about 5.0%, by weight of the composition.

Another optional active agent that may be added to the presentcompositions is a dentinal desensitizing agent to controlhypersensitivity, such as salts of potassium, calcium, strontium and tinincluding nitrate, chloride, fluoride, phosphates, pyrophosphate,polyphosphate, citrate, oxalate and sulfate.

Peroxide Source

The present compositions may contain a peroxide source for its manybenefits to the oral cavity. It has long been recognized that hydrogenperoxide and other peroxygen-containing agents are effective in curativeand/or prophylactic treatments with respect to caries, dental plaque,gingivitis, periodontitis, mouth odor, tooth stains, recurrent aphthousulcers, denture irritations, orthodontic appliance lesions,postextraction and postperiodontal surgery, traumatic oral lesions andmucosal infections, herpetic stomatitis and the like.Peroxide-containing agents in the oral cavity exert a chemomechanicalaction generating thousands of tiny oxygen bubbles produced byinteraction with tissue and salivary enzymes. The swishing action of amouthrinse enhances this inherent chemomechanical action. Such actionhas been recommended for delivery of other agents into infected gingivalcrevices. Peroxide mouthrinses prevent colonization and multiplicationof anaerobic bacteria known to be associated with periodontal disease.

Peroxide sources include peroxide compounds, perborates, percarbonates,peroxyacids, persulfates, and combinations thereof. Suitable peroxidecompounds include hydrogen peroxide, urea peroxide, calcium peroxide,sodium peroxide, zinc peroxide and mixtures thereof. A preferredpercarbonate is sodium percarbonate. Preferred persulfates are oxones.Preferred peroxide sources for use in dentifrice formulations includecalcium peroxide and urea peroxide. Hydrogen peroxide and urea peroxideare preferred for use in mouthrinse formulations. The following amountsrepresent the amount of peroxide raw material, although the peroxidesource may contain ingredients other than the peroxide raw material. Thepresent composition may contain from about 0.01% to about 30%,preferably from about 0.1% to about 10%, and more preferably from about0.5% to about 5% of a peroxide source, by weight of the composition.

Surfactants

The present compositions may also comprise surfactants, also commonlyreferred to as sudsing agents. Suitable surfactants are those which arereasonably stable and foam throughout a wide pH range. The surfactantmay be anionic, nonionic, amphoteric, zwitterionic, cationic, ormixtures thereof.

Anionic surfactants useful herein include the water-soluble salts ofalkyl sulfates having from 8 to 20 carbon atoms in the alkyl radical(e.g., sodium alkyl sulfate) and the water-soluble salts of sulfonatedmonoglycerides of fatty acids having from 8 to 20 carbon atoms. Sodiumlauryl sulfate (SLS) and sodium coconut monoglyceride sulfonates areexamples of anionic surfactants of this type. Other suitable anionicsurfactants are sarcosinates, such as sodium lauroyl sarcosinate,taurates, sodium lauryl sulfoacetate, sodium lauroyl isethionate, sodiumlaureth carboxylate, and sodium dodecyl benzenesulfonate. Mixtures ofanionic surfactants can also be employed. Many suitable anionicsurfactants are disclosed by Agricola et al., U.S. Pat. No. 3,959,458,issued May 25, 1976. The present composition typically comprises ananionic surfactant at a level of from about 0.025% to about 9%, fromabout 0.05% to about 5% in some embodiments, and from about 0.1% toabout 1% in other embodiments.

Another suitable surfactant is one selected from the group consisting ofsarcosinate surfactants, isethionate surfactants and tauratesurfactants. Preferred for use herein are alkali metal or ammonium saltsof these surfactants, such as the sodium and potassium salts of thefollowing: lauroyl sarcosinate, myristoyl sarcosinate, palmitoylsarcosinate, stearoyl sarcosinate and oleoyl sarcosinate. Thesarcosinate surfactant may be present in the compositions of the presentinvention from about 0.1% to about 2.5%, preferably from about 0.5% toabout 2.0% by weight of the total composition.

Cationic surfactants useful in the present invention include derivativesof aliphatic quaternary ammonium compounds having one long alkyl chaincontaining from about 8 to 18 carbon atoms such as lauryltrimethylammonium chloride; cetyl pyridinium chloride; cetyltrimethylammonium bromide;di-isobutylphenoxyethyl-dimethylbenzylammonium chloride; coconutalkyltrimethylammonium nitrite; cetyl pyridinium fluoride; etc.Preferred compounds are the quaternary ammonium fluorides described inU.S. Pat. No. 3,535,421, Oct. 20, 1970, to Briner et al., where saidquaternary ammonium fluorides have detergent properties. Certaincationic surfactants can also act as germicides in the compositionsdisclosed herein. Cationic surfactants such as chlorhexidine, althoughsuitable for use in the current invention, are not preferred due totheir capacity to stain the oral cavity's hard tissues. Persons skilledin the art are aware of this possibility and should incorporate cationicsurfactants with this limitation in mind.

Nonionic surfactants that can be used in the compositions of the presentinvention include compounds produced by the condensation of alkyleneoxide groups (hydrophilic in nature) with an organic hydrophobiccompound which may be aliphatic or alkylaromatic in nature. Examples ofsuitable nonionic surfactants include the Pluronics, polyethylene oxidecondensates of alkyl phenols, products derived from the condensation ofethylene oxide with the reaction product of propylene oxide and ethylenediamine, ethylene oxide condensates of aliphatic alcohols, long chaintertiary amine oxides, long chain tertiary phosphine oxides, long chaindialkyl sulfoxides and mixtures of such materials.

Zwitterionic synthetic surfactants useful in the present inventioninclude derivatives of aliphatic quaternary ammonium, phosphonium, andsulfonium compounds, in which the aliphatic radicals can be straightchain or branched, and wherein one of the aliphatic substituentscontains from about 8 to 18 carbon atoms and one contains an anionicwater-solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphateor phosphonate.

Suitable betaine surfactants are disclosed in U.S. Pat. No. 5,180,577 toPolefka et al., issued Jan. 19, 1993. Typical alkyl dimethyl betainesinclude decyl betaine or 2-(N-decyl-N,N-dimethylammonio) acetate, cocobetaine or 2-(N-coc-N,N-dimethyl ammonio) acetate, myristyl betaine,palmityl betaine, lauryl betaine, cetyl betaine, cetyl betaine, stearylbetaine, etc. The amidobetaines are exemplified by cocoamidoethylbetaine, cocoamidopropyl betaine, lauramidopropyl betaine and the like.The betaines of choice include cocoamidopropyl betaines and preferably,the lauramidopropyl betaine.

Thickening Agents

In preparing toothpaste or gels, thickening agents are added to providea desirable consistency to the composition, to provide desirable activerelease characteristics upon use, to provide shelf stability, and toprovide stability of the composition, etc. Suitable thickening agentsinclude one or a combination of carboxyvinyl polymers, carrageenan,hydroxyethyl cellulose (HEC), natural and synthetic clays (e.g., Veegumand laponite) and water soluble salts of cellulose ethers such as sodiumcarboxymethylcellulose (CMC) and sodium carboxymethyl hydroxyethylcellulose. Natural gums such as gum karaya, xanthan gum, gum arabic, andgum tragacanth can also be used. Colloidal magnesium aluminum silicateor finely divided silica can be used as part of the thickening agent tofurther improve texture.

Suitable carboxyvinyl polymers useful as thickening or gelling agentsinclude carbomers which are homopolymers of acrylic acid crosslinkedwith an alkyl ether of pentaerythritol or an alkyl ether of sucrose.Carbomers are commercially available from B.F. Goodrich as the Carbopol®series, including Carbopol 934, 940, 941, 956, and mixtures thereof.

Thickening agents are typically present in an amount from about 0.1% toabout 15%, preferably from about 2% to about 10%, more preferably fromabout 4% to about 8%, by weight of the total toothpaste or gelcomposition, can be used. Higher concentrations may be used for chewinggums, lozenges and breath mints, sachets, non-abrasive gels andsubgingival gels.

Humectants

Another optional carrier material of the present compositions is ahumectant. The humectant serves to keep toothpaste compositions fromhardening upon exposure to air, to give compositions a moist feel to themouth, and, for particular humectants, to impart desirable sweetness offlavor to toothpaste compositions. The humectant, on a pure humectantbasis, generally comprises from about 0% to about 70%, preferably fromabout 5% to about 25%, by weight of the compositions herein. Suitablehumectants for use in compositions of the subject invention includeedible polyhydric alcohols such as glycerin, sorbitol, xylitol, butyleneglycol, polyethylene glycol, propylene glycol and trimethyl glycine.

Miscellaneous Carrier Materials

Water employed in the preparation of commercially suitable oralcompositions should preferably be of low ion content and free of organicimpurities. Water may comprise up to about 99% by weight of the aqueouscompositions herein. These amounts of water include the free water whichis added plus that which is introduced with other materials, such aswith sorbitol.

The present invention may also include an alkali metal bicarbonate salt,which may serve a number of functions including abrasive, deodorant,buffering and adjusting pH. Alkali metal bicarbonate salts are solublein water and unless stabilized, tend to release carbon dioxide in anaqueous system. Sodium bicarbonate, also known as baking soda, is acommonly used alkali metal bicarbonate salt. The present composition maycontain from about 0.5% to about 30%, preferably from about 0.5% toabout 15%, and most preferably from about 0.5% to about 5% of an alkalimetal bicarbonate salt.

The pH of the present compositions may be adjusted through the use ofbuffering agents. Buffering agents, as used herein, refer to agents thatcan be used to adjust the pH of aqueous compositions such as mouthrinsesand dental solutions preferably to a range of about pH 4.0 to about pH6.0 for peroxide stability. Buffering agents include sodium bicarbonate,monosodium phosphate, trisodium phosphate, sodium hydroxide, sodiumcarbonate, sodium acid pyrophosphate, citric acid, and sodium citrate.Buffering agents are typically included at a level of from about 0.5% toabout 10%, by weight of the present compositions.

Poloxamers may be employed in the present compositions. A poloxamer isclassified as a nonionic surfactant and may also function as anemulsifying agent, binder, stabilizer, and other related functions.Poloxamers are difunctional block-polymers terminating in primaryhydroxyl groups with molecular weights ranging from 1,000 to above15,000. Poloxamers are sold under the tradename of Pluronics andPluraflo by BASF. Suitable poloxamers for this invention are Poloxamer407 and Pluraflo L4370.

Other emulsifying agents that may be used in the present compositionsinclude polymeric emulsifiers such as the Pemulen® series available fromB.F. Goodrich, and which are predominantly high molecular weightpolyacrylic acid polymers useful as emulsifiers for, hydrophobicsubstances.

Titanium dioxide may also be added to the present composition. Titaniumdioxide is a white powder which adds opacity to the compositions.Titanium dioxide generally comprises from about 0.25% to about 5% byweight of dentifrice compositions.

Other optional agents that may be used in the present compositionsinclude dimethicone copolyols selected from alkyl- andalkoxy-dimethicone copolyols, such as C12 to C20 alkyl dimethiconecopolyols and mixtures thereof. Highly preferred is cetyl dimethiconecopolyol marketed under the trade name Abil EM90. The dimethiconecopolyol is generally present in a level of from about 0.01% to about25%, preferably from about 0.1% to about 5%, more preferably from about0.5% to about 1.5% by weight. The dimethicone copolyols aid in providingpositive tooth feel benefits.

Removal of Malodor-Forming Components of Flavor Oils

A further aspect of the present invention is a refining or clean-uptreatment to remove or significantly reduce the level of undesirablesulfur-containing species in flavor oils and extracts to prepare what isreferred to herein as “select” flavor oils.

Aqueous Wash Process

A preferred cleanup treatment is an aqueous washing process which issimple, inexpensive, and easily implementable in large scale. Theaqueous medium may be all water or a water-solvent mixture with thesolvent comprising about 20% or less. The method for eliminating theundesirable components generally involves their extraction from theflavor oil into the aqueous phase. DMSO and dimethyl sulfone are highlypolar and freely soluble in water and other solvents such as alcohol.These compounds can easily be extracted from the oil with plain water ora water-alcohol mixture. The use of a co-solvent such as alcohol mayimprove the removal of less polar species such as DMS. The co-solv&ntmay be any food-grade water-miscible solvent such as ethanol,isopropanol, glycerin and propylene glycol, which will extractundesirable species such as DMS without significantly extractingdesirable components from the oil. The pH of the aqueous medium cangenerally be in the range about 3 to about 12, preferably about 7 orneutral. The exact preference in pH will depend upon the pH stability ofthe flavor oil being processed. The aqueous medium may optionallycontain salts, which may be helpful in “salting out” most of the flavorcomponents from the aqueous phase and keeping them in the flavor oilitself. Flavor oil samples are mixed with the aqueous medium at awater:oil volume ratio ranging from about 90:10 to about 10:90,preferably from about 70:30 to about 30:70. In general the more thewater the faster the rate of removal of DMSO; however too much water maylead to emulsion and render final separation of the oil phase from thewater phase difficult. Regular water may be used; USP grade water ispreferred. The process is typically conducted at room temperatureconditions. Again, the choice of temperature conditions is dependent onthe temperature stability of the flavor oil.

The water and oil phases are subjected to stirring or vigorous mixingconditions for better water and oil contact producing a turbid mixture.Mixing of the oil and water phases is continued for about 30 minutes upto 3 hours or longer. Depending on the mixing conditions and batch sizesufficient cleanup or extraction can be achieved in about 30 minutes,i.e., the level of sulfur compounds remaining in the oil has beenreduced to the target level. After mixing is stopped, the phases areallowed to separate and the oil phase is then separated from the waterphase. The separated oil phase may then be subjected to additional waterwashes with fresh water each time and/or filtration through ahydrophilic/hydrophobic adsorbent material to remove any remainingturbidity in the oil. The washed oil may also be subjected tocentrifugation or cooling to achieve separation of water left in thewashed oil. The level of DMSO and other sulfur-containing compounds inthe oil phase is quantified at certain intervals to determine ifadditional agitation/mixing or washing steps are necessary.

Improved mixing and contact of the flavor oil and water can be achievedusing high shear mixers to achieve DMSO removal over a shorter period oftime. Mixers that can be used include high shear mixers such as RossMixers for batch mixing or online mixing. Examples of suitable batchmixers include a High speed Disperser (typically used for 1 gallon-1000gallon batches) consisting of a vertical shaft and a high shear disctype blade. The blade rotates at up to about 10,000 RPM and creates aflow pattern within a stationary mix vessel. The blade creates a vortexthat pulls in the contents of the vessel to the blades sharp edge. Theblade then mechanically breaks the oil phase and disperses it in thewater phase. Another batch mixer model is the High Shear Rotor-Statormixer design consisting of a single stage rotor that turns at high speedwithin a stationary stator. As the rotating blades pass the stator, theymechanically shear the oil water phase. Small lab scale mixers have aspeed of mixing of 500-10,000 RPM (for 0.3-15 L capacity of liquid).Larger commercial scale mixers have speeds of 3600-1200 RPM (for Rotordiameters of 64 mm-330 mm) for a 15 L-22,710 L capacity of liquid. Anexample of Ultra High Shear Online mixer is a Ross model s that has afour stage or greater rotors that turn at a speed of 15000 feet perminute within a stationary stator. As the rotating blades pass thestator, they mechanically shear the contents.

In an example, 250 ml of Peppermint oil was taken in a 2 L glass beaker.To it was added 150 ml of USP water and stirred with a magnetic stirrervigorously until the oil and water formed a turbid mixture. The stirringwas continued at room temperature. At about 0.5 hr, 1 hr and 2 hrintervals, the stirring was stopped to allow the phases to separate.Within a few minutes the phases separated and a 1 ml sample of the oilwas taken for analysis. After 2 hours mixing, the phases were allowed toseparate and the upper oil layer was decanted and allowed to stand in aglass bottle for 24-48 hrs to further clarify the small amount ofturbidity remaining in the oil. The oil was then filtered through 0.45um Hydrophilic PVDF filter (Millipore) to clarify the oil and stored inglass jar until used.

The above procedure was applied to unfolded peppermint oil feedstock(supplied by I. P. Callison) and the DMSO levels in the oil phase are asfollows. DMSO was quantified using GC-MSD. As the results show, afterabout a half hour of water washing, greater than 95% of the DMSO hasbeen removed from the oil with less than 1 ppm remaining after 2 hours.

Sample DMSO (ppm, w/v) Peppermint Oil Feedstock # 1 307 35 min. washedFeedstock 12.7 60 min. washed Feedstock 16.5  2 hr. washed Feedstock <1

In addition to DMSO, the aqueous washing treatment removes other watersoluble compounds in the oils such as low molecular weight alcohols andaldehydes as well as less water-soluble compounds such as dimethylsulfide (DMS). However, the removal of DMS proceeds at a somewhat slowerrate compared to DMSO. It is believed that as the water phasesolubilizes DMSO and other organic compounds, the water phase becomesless polar, creating a better medium for removal of DMS and othercompounds of similar polarity and solubility characteristics.

In another example, the compounds removed from a sample mint oilsubjected to the present water washing process were determined. Arectified peppermint oil sample supplied by I. P. Callison was subjectedto water washing for 5 hours followed by an additional 7 hour washingstep with fresh water. Each washing step was performed with a 1:1 waterto oil mixture with gentle stirring. Mint oil from both before and afterthis washing procedure was analyzed by SPME GC-MS and the approximatereduction of each component was estimated by comparing the resultingchromatograms. A partial list of compounds whose concentrations werereduced by the washing procedure is provided in Table 2 below. There isreasonably good correlation between percent compound removed and Log P(octanol/water partition coefficient). The correlation is even betterwhen considering the molecular weight of each compound. Importantly, theconcentrations of the relatively non-polar, major components inpeppermint oil are not significantly changed by the water washingprocedure. These major components include menthol, menthone, alpha- andbeta-pinene, limonene, etc.

TABLE 2 Compounds Removed by Water Washing Peppermint Oil CompoundNumber Compound Reduced ~% Reduction 1 Methanol 95 2 Methyl formate 95 3Ethanol 95 4 Acetone 65 5 Furan 90 6 Formic acid ethyl ester 90 7 Aceticacid methyl ester 85 8 Dimethyl sulfide  99⁺ 9 Carbon disulfide 90 102-Methyl propanal 60 11 Acetic acid 70 12 2-Butanone 70 13 2-Methylfuran 70 14 3-Methyl furan 70 15 2-Methyl-1-propanol 40 16Crotonaldehyde 60 17 3-Methyl butanal 50 18 2-Methyl butanal 50 192-Pentanone 35 20 Cyclopentanol 35 21 2-Ethyl furan 20 222-Methyl-1-butanol 15 23 2-Methyl crotonaldehyde 30 24 Dimethyldisulfide 40 25 3-Methyl crotonaldehyde 30 26 Hexanal 15 27 Dimethylsulfoxide  99⁺ 28 Furfural 35 29 2-Hexenal 15 30 2,5-Diethyl THF  5

The washed or select peppermint oil was compared to traditionalrectified oil in terms of odor characteristics. Washed peppermint oiland unwashed rectified peppermint oils were odor evaluated by a panel oftrained flavorists, using a 0-100 scale, where 0 was a poor grade of oiland 100 was an excellent quality of oil. The average ratings were 33 forthe unwashed oil and 67 for the washed oil, indicating the washed oil issuperior to the unwashed rectified oil.

A typical peppermint predominant finished flavor oil for a dentifrice,containing 62% of either a rectified peppermint oil or a washedpeppermint oil was evaluated by the same expert flavor panel, using thesame scale. The average grade for the unwashed rectified oil was 58 and75 for the washed oil, indicating the washed oil to be of superiorquality.

A dentifrice containing 0.454% stannous fluoride was prepared andflavored with either rectified peppermint oil or washed peppermint oil.The dentifrices were stored at 40 C for a period of 3 months. Duringthis period the dentifrice with the washed oil did not develop any offodor while the unwashed rectified oil did develop an off odor.Evaluations were conducted by trained flavorists using a 0 (no off odor)to 10 (intense off odor) scale for presence and intensity of malodorduring the storage period. Scores assigned to the dentifrice samples areas follows. These evaluations demonstrate the stability of the waterwashed oils in the presence of a reducing agent such as stannous.

Months of Storage 1 2 3 Dentifrice w/ Unwashed Rectified Oil 3 7 7Dentifrice w/ Washed Rectified Oil 0 0 0

These series of experiments demonstrate that the water washing processcan be used to stabilize rectified flavor oils as well as prime naturalor crude flavor oils that have not gone through a refining orrectification treatment. Advantageously the water washing process issimple, efficient and economical and avoids thermal abuse of the flavoroil. The process may be sufficient to prepare commercial grade flavoroils without need for more complicated rectification processes.

Filtration Process

Another technique that may be used to remove DMSO and other sulfurcompounds from flavor oils is filtration using materials selective forsulfur compounds. Such filtration materials include commerciallyavailable materials useful as adsorbents and molecular sieves. Examplesinclude the following materials supplied by the Engelhard Corporationand Johnson Matthey Catalysts.

a) SELEXSORB CDX—a composition of Aluminum Oxide Hydrate (60-85% w/w %)and Alumino Silicate (15-40% w/w), density—42.2 cu.ft, surface area 431sq M/g, size 7×14 mesh.

b) SELEXSORB COS—a composition of Aluminum Oxide Hydrate (88-99% w/w %)and Alkali metal Oxide (1-5% w/w %), density—49.8 cu.ft., surface area255 sq M/g, size 7×14 mesh.

c) Catalyst CP367—Nickel/nickel oxide on an inert support

d) Catalyst CP366—A mixture of basic copper carbonate, basic zinccarbonate and aluminum oxide.

In an example, rectified peppermint oil supplied by I. P Callison wassubjected to filtration using the above materials as adsorbent. Theadsorbent material (60 g) was packed in a stainless steel column (fromMillipore, 3.5 cm diameter×30 cm length) fitted with a filter pad at thebottom of the column (Isopore membrane filter from Millipore, 2 um TTTPfilter). 150 ml of peppermint oil was poured on top of the column bedand the oil which passed through the column under gravity feed wascollected at the bottom. The first 75 ml of the oil was collected(designated as 1^(st) cut) followed by the second 75 ml (designated as2^(nd) cut). The filtered oil was analyzed for DMSO by the methoddescribed earlier. Results are summarized below.

TABLE 3 DMSO Removal from Peppermint Oil by Filtration Sample DMSO (ppm,w/v) % Removed 1 Rectified Peppermint Oil 197 — 2 Selexsorb COS 1^(st)cut 173 12 3 Selexsorb COS 2^(nd) cut 130 34 4 Selexsorb CDX 1^(st) cut66 66 5 Selexsorb CDX 2^(st) cut 7.4 96 6 CP 366 1^(st) cut 173 12 7 CP366 2^(nd) cut 138 30 8 CP 367 1^(st) cut 142 28 9 CP 367 2^(nd) cut 13034Countercurrent Extraction (CCE)

The technique of countercurrent extraction (CCE) may be also used toremove non-desired components from flavor oils. This technique has beenused in the flavor industry to manufacture deterpenated oils. In theoriginal patented process essential oils are deterpenated by a doublesolvent extraction process using a polar and a nonpolar solvent. Theessential oil goes through a mixing chamber and agitated with acountercurrent flow of the two solvents, resulting in continuousextraction of the terpenes into the polar solvent. In a variation of theoriginal CCE process, citrus oil is partitioned by pumping the citrusoil against a flow of hydroalcoholic solvent being pumped in theopposite direction. The terpenes are extracted from the citrus oil bythe hydroalcoholic solvent. Similarly, the CCE technique may be used toextract DMSO and other sulfur compounds using water as the extractant.The CCE technique is discussed in R. L. Swaine, “Flavoring Agents” inFood Additive Toxicology (1995), Maga & Tu (eds,).

Distillation

Flavor oils may also be fractionated using standard distillation and/orextraction techniques to remove the non-desired components. This can becarried out through standard distillation procedures such as using avacuum distillation apparatus or a spinning band column. The finalflavor oil can be reengineered or produced by selecting which componentsare desired and combining the components. For example, in mint oils,particularly those derived from a Mentha or Mentha-like source such aspeppermint oil, over 225 volatile compounds have been identified so far.However, it is also established that only a very limited number amongthe pool of volatile components actually make a substantial contributionto the overall odor of a product. Therefore, effective screening methodsare needed to separate the most odor-active compounds from the bulk ofvolatiles compounds exhibiting little or no odor. It is preferred toinclude as many components commonly found in natural mint oils aspossible to provide a full, well balanced minty taste without anyoff-taste or malodor. If a less selective fractionation or refining ofthe mint oil is done and more components are removed and not added back,the resulting mint oil flavor composition may not be as desirable.Therefore, it is desired to selectively fractionate the mint oil toprovide the most aesthetically pleasing mint flavor.

Mint oils including those commonly known as peppermint, spearmint, andcorn mint may be fractionated by distillation to remove volatile (lowerboiling point) polar compounds, which are undesirable, specifically DMSOand other sulfur-containing compounds such as sulfides and disulfides.The polar, lower boiling point components may have boiling points lessthan about 120 C, less than about 140 C, less than about 160 C or evenless than about 180 C. The distillation process would also remove otherlow molecular weight compounds such as C3-C9 aldehydes and alcohols.

The fractionated or select mint oil would be essentially free of lowboiling, polar compounds including DMSO and dimethyl sulfide. Othercomponents that are removed or significantly reduced include branchedalkanals such as 2-methylpropanal, 2-methyl butanal, and 3-methylbutanal; branched alkanols such as 2-methylpropanol, 2-methylbutanol,and 3-methylbutanol; alkenols such as Z-3-hexenol; alkenals such asE-2-hexenal; other aldehydes, alcohols and ketones such as 3-methylcyclohexanone, benzaldehyde, 1-octen-3-ol, 3-octanone, and2,3-dehydro-1,8-cineole. Specific components that the select mint oilmay include are α-pinene, β-pinene, sabinene, mycrene, α-phellandrene,α-terpinene, limonene, cis-ocimeme, eucalyptol, trans-ocimene,γ-terpiene, 3-octanol, terpineolene, sabinene hydrate, linalool,menthofuran, isopulegol, menthone, neomenthol, terpinen-4-ol,isomenthone, menthol, neoisomenthol, isomenthol, α-terpineol, pulegone,menthyl acetate, carvone, neoisomenthyl acetate, piperitone,b-bourbonene, β-caryophyllene, thymol, trans-β-farnesene, α-humulene,germacrene B, elemol, viridiflorol, eucalyptol, γ-terpinene, 1-octanol,n-amyl isovalerate, 1-methyl-4-(1-methylethyl)-trans-2-cyclohexen-1-ol,1-terpineol, α-terpineol, 4,7-dimethyl-benzofuran, citronellol,neomenthyl acetate, eugenol, ylangene, α-copaene, longifolene,α-gurjunene, caryophyllene, (+)-epi-bicylosesquiphellendrene,trans-β-farnesene, β-caryophyllene, alloaromadendrene, γ-murrolene,germacrene D, bicyclogermacrene, 8-cadiene, and terpinolene.

Method of Use

The present invention also relates to methods for cleaning teeth andpreventing undesirable oral cavity conditions including caries,microbial infection, plaque, calculus, stain and oral malodor and dentalerosion.

The method of use herein comprises contacting a subject's dental enamelsurfaces and oral mucosa with the oral compositions according to thepresent invention. The method of use may be by brushing with adentifrice, rinsing with a dentifrice slurry or mouthrinse, or chewing agum product. Other methods include contacting the topical oral gel,mouthspray, or other form with the subject's teeth and oral mucosa. Thesubject may be any person or animal whose tooth surface contact the oralcomposition. By animal is meant to include household pets or otherdomestic animals, or animals kept in captivity.

For example, a method of treatment may include a person brushing a dog'steeth with one of the dentifrice compositions. Another example wouldinclude the rinsing of a cat's mouth with an oral composition for asufficient amount of time to see a benefit. Pet care products such aschews and toys may be formulated to contain the present oralcompositions. The composition is incorporated into a relatively supplebut strong and durable material such as rawhide, ropes made from naturalor synthetic fibers, and polymeric articles made from nylon, polyesteror thermoplastic polyurethane. As the animal chews, licks or gnaws theproduct, the incorporated active elements are released into the animal'soral cavity into a salivary medium, comparable to an effective brushingor rinsing.

EXAMPLES

The following examples further describe and demonstrate embodimentswithin the scope of the present invention. These examples are givensolely for the purpose of illustration and are not to be construed aslimitations of the present invention as many variations thereof arepossible without departing from the spirit and scope.

Major components of select mint oils of the present invention are shownbelow.

Example I

Component % % α-Pinene 0.63 0.19 β-Pinene 0.90 0.23 Sabinene 0.03 0.01Myrcene 0.03 0.01 α-Terpinene 0.01 0.01 Limonene 0.50 0.05 cis-Ocimene0.01 0.01 Eucalyptol 2.64 4.71 trans-Ocimene 0.01 0.01 γ-Terpinene 0.010.01 3-Octanol 0.05 0.05 Terpineolene 0.01 0.00 Sabinene Hydrate 0.040.34 Linalool 0.07 0.59 Menthofuran 0.14 2.16 Isopulegol 0.02 0.02Menthone 16.89 2.27 Neomenthol 2.22 0.86 Terpinen-4-ol 0.03 0.04Isomenthone 3.56 0.40 Menthol 66.42 73.87 Isomenthol 0.04 0.14α-Terpineol 0.35 0.58 Pulegone 0.14 0.04 Menthyl Acetate 3.53 5.95Neoisomenthyl Acetate 0.01 0.00 Piperitone 0.06 1.35 β-Bourbonene 0.02β-Caryophyllene 0.11 3.12 Thymol 0.03 0.02 trans-β-Farnesene 0.08 0.01α-Humulene 0.02 0.24 Germacrene D 0.32 0.05 Triacetin 0.17 Germacrene B0.08 Elemol 0.89 Viridiflorol 0.03 0.03 Menthalactone 0.17

Flavor compositions containing select mint oils processed according tothe present invention are shown below. The select mint oils areessentially free of DMSO and other malodor precursor sulfur compounds.The flavor compositions containing the present mint oils are judged inorganoleptic testing to be aesthetically pleasing and can beincorporated in oral care compositions containing reducing agents suchas stannous and tea polyphenols without developing off odors or taste.

Example II

Ingredient % Select mint oil 60% Anethole 10% Menthol 25% Eucalyptol  5%

Example III

Ingredient % Select peppermint oil 42% Select spearmint oil 5% WS-3coolant 10% Anethole 7% Menthol 35% Aloe 1%

Oral compositions containing stannous ions, select mint oils in theflavor composition, and orally acceptable carriers are shown below withamounts of ingredients in weight %. These compositions are made usingconventional methods. Example IV illustrates dual phase dentifricecompositions; the first and second phases may be packaged in physicallyseparated compartments of a dispenser and dispensed side-by-sidetypically at a 50:50 ratio. Example V illustrates single phasedentifrice compositions.

Example IV

First Dentifrice Composition Second Dentifrice Composition IngredientWt. % Ingredient Wt. % Carboxymethycellulose 0.500 SodiumHydroxide^((b)) 1.000 Water 2.768 Color 0.300 Flavor 1.000 Water 21.840Glycerin 36.432 Flavor 1.000 Polyethylene Glycol 1.500 Glycerin 28.992Propylene Glycol 8.000 Sodium Gluconate 4.160 Sodium LaurylSulfate^((a)) 4.000 Stannous Chloride 3.000 Silica 28.000 Silica 23.000Benzoic Acid 0.600 Sodium Saccharin 0.300 Sodium Benzoate 0.600Poloxamer 15.500 Sodium Saccharin 0.300 Stannous Fluoride 0.908 TitaniumDioxide 1.000 Xanthan Gum 0.300 Glass H Polyphosphate 15.000 ^((a))27.9%solution ^((b))50% solution

Example V

Ingredient IVA IVB IVC IVD IVE IVF IVG Phytic Acid (20% Soln) 4.0002.000 10.000 Na Phytate (20% Soln.) 10.000 4.000 Zn Carbonate¹ 2.0001.000 2.000 Zn Oxide 5.000 Zn Pyrophosphate 8.000 Zn Lactate 2.500 NaPolyphosphate 13.000 Stannous Fluoride 0.454 0.454 0.454 0.454 0.454Sodium Fluoride 0.243 0.243 Stannous Chloride 1.500 1.000 1.500 TeaExtract 2.000 EGCG 1.000 1.000 Sodium Gluconate 0.672 0.600 0.672 0.6000.672 0.652 2.100 Sorbitol Soln 34.275 35.785 34.275 35.785 34.27537.496 Glycerin 38.519 14.425 HEC 0.300 0.300 0.300 0.300 0.300 Na CMC1.200 1.300 1.200 1.300 1.200 0.600 Carrageenan 0.500 0.500 0.500 0.5000.500 0.600 Xanthan Gum 0.350 0.700 PEG 7.000 Propylene Glycol 7.000Silica Abrasive 20.000 16.000 20.000 16.000 20.000 25.000 20.000 TiO₂(Anatase) 0.525 0.525 0.525 0.525 0.525 0.525 SLS (28% Soln.) 4.0007.500 4.000 7.500 4.000 2.500 5.000 Na Saccharin 0.250 0.250 0.250 0.2500.250 0.500 0.300 Flavor 0.950 0.950 0.950 0.950 0.950 0.800 1.000 NaOH0.006 0.122 0.006 0.122 0.006 0.600 Na Phosphate Tribasic 1.100 Waterand Minors, e.g., QS QS QS QS QS QS QS Colon soln. ¹Zinc Carbonate ACsupplied by Bruggemann Chemical: Newtown Square, PA, USA

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this written document conflicts with any meaningor definition of the term in a document incorporated by reference, themeaning or definition assigned to the term in this written documentshall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A method of processing a flavor oil or flavor oilextract to substantially eliminate dimethyl sulfoxide responsible forgeneration of malodor and off-taste comprising: (a) combining the flavoroil or flavor oil extract phase with an aqueous phase consistingessentially of water and no more than about 20% of one or more of asolvent selected from ethanol, isopropanol, glycerin and propyleneglycol and having about a neutral pH, wherein the water:oil volume ratioranges from about 70:30 to about 30:70, (b) subjecting the aqueous phaseand the flavor oil or flavor oil extract phase to mixing conditionssufficient to allow contact between the flavor oil or flavor oil extractand water phases for effective extraction of dimethyl sulfoxide into thewater phase, (c) allowing the phases to separate, (d) collecting thewashed flavor oil or flavor oil extract phase, and (e) combining thewashed flavor oil or flavor oil extract phase with a stannous ionsource; wherein the washed flavor oil or flavor oil extract comprises nomore than about 20 ppm by weight per volume of the flavor oil or flavoroil extract of dimethyl sulfoxide.
 2. The method of claim 1 furthercomprising clarifying the washed flavor oil or flavor oil extract byfiltration through a hydrophilic/hydrophobic adsorbent material, bycentrifugation or by cooling to achieve separation of water left in thewashed flavor oil or flavor oil extract.
 3. The method of claim 1,wherein mixing of the flavor oil or flavor oil extract and aqueousphases is conducted from at least about 30 minutes to about 6 hours. 4.The method of claim 1, wherein the phases are mixed under high-shear. 5.The method of claim 1, wherein the flavor oil or flavor oil extract isderived from peppermint, corn mint, or spearmint.
 6. A method ofprocessing a flavor oil or flavor oil extract to substantially eliminatedimethyl sulfoxide responsible for generation of malodor and off-tastecomprising filtering the flavor oil or the flavor oil extract through anadsorbent material comprising a metal oxide, combining the filteredflavor oil or flavor oil extract phase with a stannous ion source,wherein the filtered flavor oil or flavor oil extract comprises no morethan about 20 ppm by weight per volume of the flavor oil or flavorextract of dimethyl sulfoxide.
 7. The method of claim 6, wherein theflavor oil or flavor oil extract is derived from peppermint, corn mint,or spearmint.